Identification of Alternative Hosts of Xylella Fastidiosa in the Washington, D.C., Area Using Nested Polymerase Chain Reaction (PCR)

Abstract

A survey of 27 herbaceous and woody plant taxa was conducted to identify possible alternative hosts of the xylem-limited bacterium, Xylellafastidiosa. Samples were collected from wild and cultivated plants inhabiting and surrounding the National Park Service Daingerfield Island Nursery in Alexandria, Virginia, and from national parks in Washington, D.C. These samples were analyzed using up to 3 different bacterial extraction methods and a 2-step, nested polymerase chain reaction (PCR) amplification using oligonucleotide primers specific to X. fastidiosa. Six out of the 27 sampled plant taxa tested positive. Acer negundo, Aesculus x hybrid, Cdastrus orbiculata, Cornus florida, and Hedera helix have not been previously confirmed as hosts, while Vitis species have been described as wild and cultivated hosts in numerous studies. Eleven of the 27 taxa could not be tested due to failure to amplify X. fastidiosa DNA in the positive controls, regardless of the extraction method.